CN114438396B - Production method of round steel for high-strength bolt for severe cold resistant power transmission tower - Google Patents
Production method of round steel for high-strength bolt for severe cold resistant power transmission tower Download PDFInfo
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- CN114438396B CN114438396B CN202111586293.2A CN202111586293A CN114438396B CN 114438396 B CN114438396 B CN 114438396B CN 202111586293 A CN202111586293 A CN 202111586293A CN 114438396 B CN114438396 B CN 114438396B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
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Abstract
The invention relates to the technical field of steel production, in particular to a method for producing round steel for a high-strength bolt for a severe cold resistant power transmission tower.
Description
Technical Field
The invention relates to the technical field of steel production, in particular to a method for producing a round steel for a high-strength bolt for a severe cold resistant power transmission tower.
Background
In recent years, large hydropower stations such as Xiluodie, homey dam, white Crane beach and the like are respectively built in Jinsha river in the southwest region, are used as key projects for developing western and eastern power transmission in the western region of China, and are also matched with a plurality of extra-high voltage transmission projects of more than 800 kilovolts, and transmission lines mostly adopt transmission towers, need to pass through high-altitude regions such as the southwest region and finally enter regions such as Jiangsu and Zhejiang.
In high altitude areas such as southwest areas, extreme conditions such as large day and night temperature difference and severe cold in winter are easy to occur, and the environmental temperature reaches below minus 20 ℃ and is lower than the brittle transition temperature of conventional materials. Some conventional steel for fasteners used in power transmission towers have a tendency to cause a reduction in toughness of materials in such a low-temperature environment, and may be broken due to cold brittleness, thereby losing the performance of the fasteners and seriously affecting the equipment safety of the power transmission towers and the overall safety of the power transmission line.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a production method of round steel for a high-strength bolt for a severe cold resistant power transmission tower. The bolt made of the round steel has high strength, can withstand extreme weather tests, and ensures the equipment safety and the line safety of the power transmission tower.
The technical scheme adopted by the invention for solving the technical problems is as follows: a production method of round steel for a high-strength bolt for a severe cold resistant power transmission tower is characterized by comprising the following steps:
material selecting step S1: selecting blast furnace molten iron and scrap steel as raw materials;
an LD smelting step S2: adopting an alkaline oxygen top-bottom combined blowing converter with nominal capacity of 100 tons, adding a slagging agent, introducing oxygen for smelting, and forming primary molten steel after decarburization, temperature rise and impurity removal; carrying out preliminary deoxidation alloying operation behind a converter;
and an LF refining step S3: refining operation is carried out by adopting an LF ladle refining furnace with nominal capacity of 120 tons;
VD refining step S4: vacuumizing by adopting a three-stage mechanical vacuum pump system, wherein the vacuum degree is below 67Pa, and removing H elements, impurities and other gases in the molten steel;
a continuous casting step S5: adopting an R10m continuous casting machine to carry out continuous casting operation, wherein the specification of the casting blank is 150 × 150mm 2 (ii) a Forming a qualified casting blank after the casting blank is subjected to slow cooling and inspection steps;
a steel rolling step S6: heating the casting blank by adopting a stepping heating furnace, descaling by adopting high-pressure water to ensure that the surface of the red blank has no iron scale, and performing primary rolling, intermediate rolling and finish rolling by adopting a horizontal and vertical cross rolling mill to form phi 35 round steel;
a finishing step S7: after the round steel is sawed and cooled, the round steel is straightened and chamfered, and finally forms a finished product through eddy current and ultrasonic flaw detection means.
Preferably, in the step S2, the auxiliary materials added for the preliminary deoxidation alloying after the converter furnace are any one or at least two of Al blocks, silicon-manganese alloy, high-carbon ferrochrome, ferromolybdenum and refined slag.
Preferably, the refining method in step S3 is as follows:
s31, carrying out deoxidation operation by adopting auxiliary materials such as calcium silicate powder, silicon carbide, al particles and the like;
s32, adjusting the components of refining top slag by adopting materials such as fluorite, refining slag and the like;
s33, adopting high-carbon ferrochrome, ferromolybdenum, ferroniobium, nickel plates and other alloys to carry out microalloying adjustment on the molten steel to form the molten steel with the components meeting the requirements.
Preferably, the molten steel in the step S33 contains the following components in percentage by weight: 0.40 to 0.45 percent of C, 0.20 to 0.30 percent of Si, 0.65 to 0.75 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.015 percent of S, 1.05 to 1.15 percent of Cr, 0.15 to 0.20 percent of Mo, 0.015 to 0.030 percent of Alt, 0.05 to 0.10 percent of Nb and 0.30 to 0.50 percent of Ni.
Preferably, the compression ratio of the qualified casting blank in the step S5 is not less than 10.
The invention has the beneficial effects that through the innovative steel smelting technology, the component design and the production adjustment control technology, the produced round steel for the high-strength bolt can be used for the high-strength bolt fastener for the power transmission tower in the western high-altitude area, can adapt to extreme conditions such as large temperature difference between day and night and severe cold in winter, ensures that the high-strength fastener of the power transmission tower keeps qualified mechanical property in the extremely severe environment of the high-altitude area, and ensures the equipment safety of the power transmission tower and the safety of the power transmission line.
Drawings
The invention is further illustrated with reference to the following figures and examples.
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
As shown in fig. 1, the invention is a schematic structural diagram, and the method for producing the round steel for the high-strength bolt for the severe cold resistant power transmission tower is characterized by comprising the following steps:
material selecting step S1: selecting blast furnace molten iron and scrap steel as raw materials;
an LD smelting step S2: adopting an alkaline oxygen top-bottom combined blowing converter with the nominal capacity of 100 tons, adding a slagging agent, introducing oxygen for smelting, and forming primary molten steel after decarburization, temperature rise and impurity removal; carrying out preliminary deoxidation alloying operation after the converter is used;
and an LF refining step S3: refining operation is carried out by adopting an LF ladle refining furnace with nominal capacity of 120 tons;
VD refining step S4: vacuumizing by adopting a three-stage mechanical vacuum pump system, wherein the vacuum degree is below 67Pa, and removing H elements, impurities and other gases in the molten steel;
and a continuous casting step S5: adopting an R10m continuous casting machine to carry out continuous casting operation, wherein the specification of the casting blank is 150 x 150mm 2 (ii) a Forming a qualified casting blank after the casting blank is subjected to slow cooling and inspection steps;
and a steel rolling step S6: heating the casting blank by adopting a stepping heating furnace, descaling by adopting high-pressure water to ensure that the surface of the red blank has no iron scale, and performing primary rolling, intermediate rolling and finish rolling by adopting a horizontal and vertical cross rolling mill to form phi 35 round steel;
a finishing step S7: after sawing and cooling, the round steel is straightened and chamfered, and finally forms a finished product through eddy current and ultrasonic flaw detection means.
The invention selects blast furnace molten iron and scrap steel as raw materials, which can reduce the influence of residual elements and harmful elements on the performance of steel; removing impurities and performing preliminary deoxidation alloying through an LD smelting step to prepare for a subsequent LF refining step; alloy components are controlled in the LF refining step, so that the quality of steel is ensured; during VD refining, H elements, impurities and other gases are removed better by vacuumizing, maintaining the vacuum degree and the vacuum time; in the continuous casting step, the compression ratio of a casting blank is controlled to ensure the quality of a finished product; finally, the high-strength round steel is obtained, and the high-strength bolt fastener made of the round steel is good in toughness, capable of avoiding cold-brittle fracture and capable of adapting to extreme conditions such as large temperature difference between day and night and severe cold in winter.
Preferably, in the step S2, the auxiliary materials added for the preliminary deoxidation alloying after the converter furnace are any one or at least two of Al blocks, silicon-manganese alloy, high-carbon ferrochrome, ferromolybdenum and refined slag.
Preferably, the refining in step S3 is specifically as follows:
s31, carrying out deoxidation operation by adopting auxiliary materials such as calcium silicon powder, silicon carbide, al particles and the like;
s32, adjusting the components of the refining top slag by adopting materials such as fluorite, refining slag and the like;
s33, microalloying and adjusting the molten steel by adopting alloys such as high-carbon ferrochrome, ferromolybdenum, ferroniobium, nickel plates and the like to form the molten steel with components meeting the requirements.
Preferably, the molten steel in the step S33 contains the following components in percentage by weight: 0.40 to 0.45 percent of C, 0.20 to 0.30 percent of Si, 0.65 to 0.75 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.015 percent of S, 1.05 to 1.15 percent of Cr, 0.15 to 0.20 percent of Mo, 0.015 to 0.030 percent of Alt, 0.05 to 0.10 percent of Nb and 0.30 to 0.50 percent of Ni.
Preferably, the compression ratio of the qualified casting blank in the step S5 is not less than 10.
Examples
High-quality steel scrap and blast furnace molten iron are adopted, and LD smelting, LF refining, VD refining, continuous casting, steel rolling and finishing are carried out to prepare the high-strength bolt steel for the severe cold resistant power transmission tower, and the components are as follows:
the tensile strength of the steel obtained in the embodiment is more than or equal to 1050MPa, and the yield strength is more than or equal to 1000MPa; the manufactured high-strength bolt meets the mechanical property requirement of a 10.9-grade high-strength bolt. The impact toughness at minus 40 ℃ is more than or equal to 85J.
Comparative example
In the common high-strength bolt in the prior art, the impact toughness at minus 40 ℃ is less than or equal to 50J.
Therefore, compared with the common high-strength bolt of the comparative example, the impact toughness of the high-strength bolt at 40 ℃ below zero is improved by about 50%, so that the high-strength bolt has good toughness, can avoid cold-brittle fracture, and can adapt to extreme conditions such as large temperature difference between day and night, severe cold in winter and the like.
The foregoing description is intended to be illustrative rather than limiting, and it will be appreciated by those skilled in the art that many modifications, variations or equivalents may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (3)
1. A production method of round steel for a high-strength bolt for a severe cold resistant power transmission tower is characterized by comprising the following steps:
material selecting step S1: selecting blast furnace molten iron and scrap steel as raw materials;
an LD smelting step S2: adopting an alkaline oxygen top-bottom combined blowing converter with the nominal capacity of 100 tons, adding a slagging agent, introducing oxygen for smelting, and forming primary molten steel after decarburization, temperature rise and impurity removal; carrying out preliminary deoxidation alloying operation after the converter is used;
and an LF refining step S3: refining operation is carried out by adopting an LF ladle refining furnace with nominal capacity of 120 tons;
VD refining step S4: vacuumizing by adopting a three-stage mechanical vacuum pump system, wherein the vacuum degree is below 67Pa, and removing H elements, impurities and other gases in the molten steel;
and a continuous casting step S5: adopting an R10m continuous casting machine to carry out continuous casting operation, wherein the specification of the casting blank is 150 × 150mm 2 (ii) a Forming a qualified casting blank after the casting blank is subjected to slow cooling and inspection steps;
and a steel rolling step S6: heating the casting blank by adopting a stepping heating furnace, descaling by adopting high-pressure water to ensure that the surface of the red blank has no iron scale, and performing primary rolling, intermediate rolling and finish rolling by adopting a horizontal and vertical cross rolling mill to form phi 35 round steel;
a finishing step S7: after sawing and cooling, the round steel is straightened and chamfered, and finally forms a finished product through eddy current and ultrasonic flaw detection means, wherein the tensile strength of the finished product is more than or equal to 1050MPa, the yield strength is more than or equal to 1000MPa, and the impact toughness at minus 40 ℃ is more than or equal to 85J;
the refining method in the step S3 comprises the following steps:
s31, carrying out deoxidation operation by adopting silicon calcium powder, silicon carbide and Al particle auxiliary materials;
s32, adjusting the components of refining top slag by adopting fluorite and refining slag materials;
s33, adopting high-carbon ferrochrome, ferromolybdenum, ferroniobium and nickel plate alloy to carry out microalloying adjustment on the molten steel to form molten steel with components meeting requirements;
the molten steel in the step S33 comprises the following components in percentage by weight: 0.40 to 0.45 percent of C, 0.20 to 0.30 percent of Si, 0.65 to 0.75 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.015 percent of S, 1.05 to 1.15 percent of Cr, 0.15 to 0.20 percent of Mo, 0.015 to 0.030 percent of Alt, 0.05 to 0.10 percent of Nb and 0.30 to 0.50 percent of Ni.
2. The method for producing the round steel for the high-strength bolt for the severe cold resistant power transmission tower according to claim 1, wherein in the step S2, the auxiliary materials added for the preliminary deoxidation alloying operation after the converter furnace are any one or at least two of Al blocks, silicon-manganese alloy, high-carbon ferrochrome, ferromolybdenum and refined slag.
3. The method for producing the round steel for the high-strength bolt for the severe cold resistant power transmission tower according to claim 1, wherein the compression ratio of the qualified casting blank in the step S5 is not less than 10.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111586293.2A CN114438396B (en) | 2021-12-23 | 2021-12-23 | Production method of round steel for high-strength bolt for severe cold resistant power transmission tower |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111586293.2A CN114438396B (en) | 2021-12-23 | 2021-12-23 | Production method of round steel for high-strength bolt for severe cold resistant power transmission tower |
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| CN114438396A CN114438396A (en) | 2022-05-06 |
| CN114438396B true CN114438396B (en) | 2023-03-14 |
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| JP4867638B2 (en) * | 2006-12-21 | 2012-02-01 | Ｊｆｅスチール株式会社 | High-strength bolts with excellent delayed fracture resistance and corrosion resistance |
| CN104911502B (en) * | 2015-05-29 | 2017-02-01 | 武钢集团昆明钢铁股份有限公司 | 1080MPa grade high strength prestressed finish rolled threaded reinforcing bar and preparation method thereof |
| CN112609035A (en) * | 2020-12-24 | 2021-04-06 | 常州东方特钢有限公司 | Production method of cold-resistant steel for automobile structural pipe |
| CN113604738A (en) * | 2021-08-02 | 2021-11-05 | 江苏永钢集团有限公司 | Round steel for high-strength and high-toughness large-specification wind power bolt and manufacturing method thereof |
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